title: Naturally occurring antibodies to liposomes. II. Specificity and electrophoretic pattern of rabbit antibodies reacting with sphingomyelin-containing liposomes.
abstract: Sera obtained from rabbits after immunization with a variety of unrelated antigens contain antibodies that induce complement- (C) mediated lysis of sphingomyelin-containing liposomes in the absence of the relevant antigen from the membrane. Absorption or inhibition with dimyristoyl-phosphatidyl choline-containing liposomes were less effective than with sphingomyelin-containing liposomes in decreasing or abolishing C-dependent lysis of target-liposomes. Phosphoryl choline chloride inhibited the C-dependent lysis mediated by these antibodies, but only when used in high molar excess and in the presence of low antibody concentrations. Purified anti-liposome antibodies displayed an isoelectric focusing pattern consistent with a polyclonal response. The findings confirm the antibody nature of the anti-liposome activity of rabbit sera and indicate that their predominant specificity is directed against conformations of the phospholipid molecule in which the polar (phosphoryl choline) group does not have a major contribution.
mesh_terms: D000042:Absorption; D000818:Animals; D000918:Antibody Specificity; D001667:Binding, Competitive; D002417:Cattle; D004134:Dimyristoylphosphatidylcholine; D004591:Electrophoresis, Polyacrylamide Gel; D007113:Immunity, Innate; D007525:Isoelectric Focusing; D008081:Liposomes / Q000276:immunology*; D009169:Mycobacterium tuberculosis / Q000276:immunology; D010713:Phosphatidylcholines / Q000494:pharmacology; D010767:Phosphorylcholine; D011817:Rabbits; D012756:Sheep; D013109:Sphingomyelins / Q000494:pharmacology*; D013296:Streptococcus pneumoniae / Q000276:immunology
chemical_list: D008081:Liposomes; D010713:Phosphatidylcholines; D013109:Sphingomyelins; D010767:Phosphorylcholine; D004134:Dimyristoylphosphatidylcholine